This invention will be discussed in general with respect to aortic aneurysms and the use of an implantable device such as a stent graft to bridge an aneurysm and in particular in the descending aorta but the invention is not so limited and may be used for any region of the human or animal body and any type of implantable device.
A stent graft can be used to bridge an aortic aneurysm but where there are side branch arteries from the aorta it is necessary to have side branches extending from the stent graft to give a blood supply to as many side branch arteries as possible.
There are four main side branch arteries in the descending aorta. These are the celiac artery, the superior mesenteric artery, the right renal artery and the left renal artery. There are also a number of other minor side branch arteries but these are smaller and generally cannot be catheterised to enable placement of a side branch graft. One of these sets of arteries is the intercostal arteries. Stent grafts can block or inhibit spinal cord blood supply through these arteries, at least temporarily.
After an endovascular operation to place a stent graft into the descending aorta to repair a thoraco-abdominal aortic aneurysm (TAAA) for instance, the human or animal body can in time adapt to lack of blood supply from some arteries which are occluded by the stent graft. For instance blood supply via the intercostal arteries to the spinal cord can be alternatively achieved via other arteries such as for instance the celiac artery, the superior mesenteric artery, lumbar and internal iliac arteries.
There can be a problem, however, of blood supply immediately after an operation, causing a risk of paraplegia or spinal cord ischemia, and it is the object of this invention to provide a possible solution or at least provide the physician with a useful alternative.